Hmmm.. I think its the IP address of your computer i.e. goto http://whatismyipaddress.com/ and get your IP address and use it below.
RewriteCond %{REMOTE_HOST} !^123.45.67.8
RewriteRule (.*) http://www.vietnamvisacorp.com/$1 [R=301,L]
I am sorry, not much of an Apache expert.